The invention relates to a functionalized and polymerizable polymer, a process for the preparation thereof, the use thereof and compositions containing the polymer.
Polymers functionalized by carboxyl groups, such as poly(acrylic acid) and poly(methacrylic acid) as well as homo- and copolymers based on maleic acid or fumaric acid, are widely used in technology. They are used, inter alia, as flocculating agents or thickeners, as a component of coatings or adhesives and as a leather or textile auxiliary (cf Ullmann""s Encyclopedia of Industrial Chemistry, 5th Ed., Vol. A21, VCH Publisher, Weinheim 1992, page 143 et seq. and Encyclopedia of Polymer Science and Engineering, Vol. 9, Wiley and Sons, New York 1987, page 225 et seq.). Polyacrylic acid is also used in the dental field as a constituent of so-called carboxylate cements or of aluminosilicate-polyacrylic acid cements (cf K. Kxc3x6rber, K. Ludwig, Zahnxc3xa4rztliche Werkstoffkunde und Technologie, Thieme-Verlag, Stuttgart-New York 1982, page 57 et seq.).
Furthermore, in recent years, so-called glass ionomer cements have gained great practical interest. These are cements which are prepared from mixtures of a Caxe2x80x94Alxe2x80x94F silicate glass powder with an aqueous solution, e.g. of an acrylic acid-maleic acid copolymer. They are used in the dental field as fixing cements, filling materials, base materials, adhesives or fissure sealants (cf A. D. Wilson, J. D. McLean, Glasionomerzement, Quintessens-Verlag, Berlin 1988, page 21 et seq.). In the case of so-called light-curing glass ionomer cements, polymerizable cross-linking monomers and initiators are also added to customary glass ionomer cements, which results in an acceleration of material curing and improvement of the mechanical properties. A further improvement in material properties can be achieved by the use of polycarboxylic acids which bear lateral groups capable of polymerization. Such polycarboxylic acids can be prepared e.g. by polymer-analogous reaction of polyacrylic acid with allyl isocyanate oder 2-isocyanatoethyl methacrylate (cf EP-B-323 120 and S. B. Mitra, Amer. Chem. Soc., Polym. Div., Polym. Prep. 32, (1991) page 517) or e.g. by reaction of oligomaleic acid anhydride with 2-hydroxyethyl methacrylate (cf EP-B-219 058). Corresponding polymers can also be obtained by polymer-analogous reaction of polyacrylic acid with glycidyl methacrylate (cf U.S. Pat. No. 3,872,047). With all these reactions, however, the known disadvantages of polymer-analogous reactions, such as impeded accessibility of the functional groups, non-separability of by-products or the occurrence of ring-closure reactions or crosslinking reactions, have to be accepted (cf M. Fedtke, Reaktionen an Polymeren, Verlag fxc3xcr Grundstoffindustrie, Leipzig 1985, page 17 et seq.).
Furthermore, it is known that mono- or bicyclic alkenes, such as e.g. cyclopentene or norbornene, can be subjected to a ring-opening polymerization with catalysts of olef in metathesis, e.g. MoO3/Al2O3 or WCl6/(C2H5)3Al. This type of reaction is also called metathesis polymerization (cf Encyclopedia of Polymer Science and Engineering, Vol. 9, J. Wiley and Sons, New York, 1987, page 634 et seq. and K. J. Ivin, Olef in Metathesis, Academic Press, London 1983). A ring-opening metathesis polymerization (ROMP) is also possible in the case of polar compounds, such as 7-oxa-bicyclo[2.2.1]hept-5-ene derivatives which have polar substituents in the 2- or 3-position, such as alkoxy, hydroxyalkyl, alkoxycarbonyl, carboxyl or carboxylic acid anhydride, in aqueous-alcoholic reaction medium with ruthenium(III) chloride as catalyst (cf B. M. Novak, R. H. Grubbs, J. Amer. Chem. Soc. 110, (1988) page 960, 7542, W. J. Feast, D. B. Mallison, Polymer 32 (1991) page 558 and A. Y. Lu et al. Makromol. Chem. Phys. 195 (1994) page 1273). Furthermore, the ROMP of cyclooct-5-enyl methacrylate is also known which results in radically crosslinkable polymers (cf B. R. Maughon, R. H. Grubbs, Amer. Chem. Soc., Polym. Div., Polym. Prep. 36, (1995) page 471).
Moreover, bicyclic methacrylates are also known. Thus, U.S. Pat. No. 4,054,233 discloses the synthesis and polymerization of bicyclo[2.2.1]hept-5-en-2-ylmethyl methacrylate in conjunction with peroxidically crosslinkable layers. According to SU-A-1 776 673 and Chem. Abst. 199, 272563, bicyclo[2.2.1]hept-5-en-2-ylmethyl methacrylate or borneol methacrylate is used in the preparation of PVC having improved heat stability. CA-A-1 013 095 discloses adhesive polymers based on reaction products of bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid anhydride with hydroxyalkyl (meth)acrylates, such as 2-hydroxyethyl methacrylate. Radically crosslinkable polyimides which are accessible via 7-oxa-5,6-dicarboxyimid-N-yl-bicyclo[2.2.1]hept-2-ene acrylate are known from T. M. Pyriadi, I. U. Altmamimi, Macromol. Rep. A31, (1994) page 191. Finally, products of the reaction of dicyclopentadiene with (meth)acrylic acid are also known (cf S. Teshigahara, Y. Kano, Toso Kenkyu Hokoko, 35 (1991) page 47 and Chem. Abstr. 116, 84740).
The object of the invention is to make available a functionalized and polymerizable polymer which can be prepared in a simple manner and radically polymerized at room temperature, exhibits good adhesion to various substrates, forms cements with reactive fillers and therefore can be used in particular as a component of cements, coating materials, adhesives or composites and preferably of dental materials. This object is achieved by the functionalized and polymerizable polymer according to Claims 1 and 2.
The subject matter of the present invention is also a process for the preparation of the polymer according to Claim 3, the use thereof according to Claims 4 and 5, and compositions containing the polymer according to Claims 6 to 9.
The functionalized and polymerizable polymer according to the invention is characterized by the fact that it has the following repeat units (IA), (IB) and (IC): 
where X, Axe2x80x94B, Y, P, Z, U, V, T, R1, R2, R3, R4 and R5 independently of one another have the following meanings:
X=CH2 or O;
Axe2x80x94B=Cxe2x80x94C or Cxe2x95x90C;
Y=CH2O, COxe2x80x94O or COOxe2x88x92R1xe2x80x94O, where R1=substituted or unsubstituted C1 to C5 alkylene or oxyalkylene;
P=a polymerizable group, namely CH2xe2x95x90CHxe2x80x94COxe2x80x94, CH2xe2x95x90C(CH3)xe2x80x94COxe2x80x94, CH2xe2x95x90CHxe2x80x94CH2xe2x80x94 or CH2xe2x95x90CHxe2x80x94C6H5xe2x80x94CH2xe2x80x94;
Z=H, COOH, substituted or unsubstituted C1 to C12 alkyl or COOR4, where R4=substituted or unsubstituted C1 to C12 alkyl or C6 to C14 aryl,
U=COOH or COOR5, where R5=substituted or unsubstituted C1 to C12 alkyl or C6 to C14 aryl;
V=H, COOH, CH2xe2x80x94OH, OR2 or COxe2x80x94OR2, where R=substituted or unsubstituted C1 to C12 alkyl or C6 to C14 aryl; and
T=O, NH or NHR3, where R3=substituted or unsubstituted C1 to C12 alkyl or C6 to C14 aryl; and
where the mole fraction a of the unit (IA), the mole fraction b of the unit (IB) and the mole fraction c of the unit (IC) are as follows:
a=0.05 to 1.0;
b=0 to 0.95; and
c=0 to 0.90.
The polymer is preferably built up from the units (IA) and optionally (ID) and optionally (IC).
Furthermore, Axe2x80x94B and X are also chosen independently of one another in the individual five-membered rings.
The alkyl and aryl groups of Z, R1, R2, R3, R4 and R5 can optionally be substituted by one or more simple functional groups, in particular COOH, OH, C1 to C6 alkoxy or halogen.
For simplication, the polymer according to the invention is in the following represented by the general formula (I): 
The type of simplifying representation chosen in formula (I) is also used analogously for other compounds in the description and in the claims.
Preferred definitions which can be chosen independently of one another exist for the above-mentioned variables of the polymer according to the invention, these definitions being as follows:
X=CH2 or O;
Axe2x80x94B=Cxe2x80x94C;
Y=CH2O or COxe2x80x94Oxe2x80x94R1xe2x80x94O;
R1=CH2CH2 or CH2xe2x80x94CHOHxe2x80x94CH2;
P=CH2xe2x95x90C(CH3)xe2x80x94CO;
Z=H or COOH;
R4=CH3, C2H5 or phenyl;
U=COOH;
R5=CH3, C2H5 or phenyl;
V=H or COOH;
R2=CH3 or C2H5;
T=O;
R3=CH3 or phenyl;
a=0.10 to 0.80;
b=0 to 0.80, in particular more than 0 and up to 0.80; and/or
c=0 to 0.60, in particular more than 0 and up to 0.60.
Preferred compounds are accordingly those in which at least one of the variables of the formula (I) has the preferred definition described above.
In order to prepare the polymer according to the invention, the bicyclic compound (II) or optionally mixtures of (II) with the bicyclic compound (III) and/or the bicyclic compound (IV) are subjected to a ring-opening metathesis polymerization in the presence of a catalyst, and protective groups present are then cleaved off when protected educts are used. After the metathesis polymerization, the positions of A and B with the radicals bound thereto are no longer distinguishable from one another. Instead of (II), (III) and (IV), those compounds in which only the positions of A and B with the radicals bound thereto are exchanged can also be used as educts. 
Examples of suitable protective groups are trimethylsilyl groups and tetrahydropyranyl groups.
In addition, the polymer (I) according to the invention is also obtainable by polymer-analogous reaction of the polymer (V) with the polymerizable educt P-halogen, in accordance with the reaction equation below: 
The polymer (V) can be prepared in the presence of a suitable catalyst by ring-opening metathesis polymerization of a mixture of the bicyclic compound (VI) with the bicyclic compound (III) and the bicyclic compound (IV). 
It is known that catalyst systems based on compounds of the transition metals of the IVth to VIIIth sub-group can be used as catalysts for ring-opening metathesis polymerization (ROMP) (cf Encyclopedia of Polymer Science and Engineering, Vol. 9, J. Wiley and Sons, New York 1987, page 648 et seq.).
Above all, compounds of Mo, W, Ru, Os and Ir are used. Customary catalysts are based on metal carbene complexes, such as Ru, W or Mo carbene complexes (cf R. R. Schrock, Acc. Chem. Res. 23 (1990) 158). Simple salts such as K2RuCl5 or the hydrates of RuCl3 or OsCl3 are suitable in particular for the ring-opening metathesis polymerization of polar monomers (W. J. Feast, D. B. Harrison, Polymer 32 (1991) 558). Various solvents can be used depending on the catalyst used. Thus, e.g. in the case of metal carbene complexes, aprotic solvents such as THF, benzene, chlorobenzene, toluene, pentane or dichloromethane are used, whereas with RuCl3 the ring-opening metathesis polymerization is usually carried out in an aqueous-alcoholic medium. The use of 1-alkenes, cis-2-butene-1,4-diol or acrylic acid in particular is suitable for controlling the molecular weight of the polymers obtained. The temperature at which the polymerization is carried out is normally in the range from 15-60xc2x0 C. when metal carbenes are used as catalyst, and from 40 to 70xc2x0 C. in the case of e.g. RuCl3.
The bicyclic compounds of the formulae (II), (III), (IV) and (VI) which are used as educts for the preparation of the polymer according to the invention are known or can be prepared in a simple manner by known methods.
Representatives of the general formula (II) are e.g. bicyclo[2.2.1]hept-5-en-2-ylmethylallyl ether (VII), bicyclo[2.2.1]hept-5-en-2-ylmethyl acrylate (VIII), bicyclo[2.2.1]hept-2,5-dien-2-ylmethyl methacrylate (IX), 7-oxabicyclo[2.2.1]hept-5-en-2-ylmethyl methacrylate (X), bicyclo[2.2.1]hept-5-en-2-ylmethyl methacrylate (XI) or the 1:1 reaction product (XII) of bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid anhydride and 2-hydroxyethyl methacrylate, where (XI) and (XII) are known. 
Representatives of the general formula (III) are e.g. bicyclo[2.2.1]hept-5-ene-2-carboxylic acid (XIII), bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid monomethyl ester (XIV), bicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylic acid (XV), bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid (XVI) or 7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid (XVII), where (XVI) and (XVII) are known. 
Representatives of the general formula (IV) are e.g. bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid imide (XVIII), bicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylic acid anhydride (XIX), bicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylic acid-N-phenylimide (XX), bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid anhydride (XXI) or 7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid anhydride (XXII), where (XXI) and (XXII) (cf O. Diels, K. Alder, Chem. Ber. 62, (1929) page 557) are known. 
Representatives of the general formula (VI) are e.g. 7-oxabicyclo[2.2.1]hept-5-ene-2-carboxylic acid (XXIII), 7-oxabicyclo[2.2.1]hept-2,5-diene-2-carboxylic acid (XXIV), bicyclo[2.2.1]hept-5-ene-2-carboxylic acid-2-hydroxyethyl ester (XXV), bicyclo[2.2.1]hept-5-ene-2-methanol (XXVI) or bicyclo[2.2.1]hept-5-ene-2-carboxylic acid (XIII), where (XXVI) and (XIII) are known. 
The bicyclic compounds of the formulae (II) to (IV) and those of the formula (VI) can be prepared in a simple manner by way of a Diels-Alder reaction (cf H. Wollweber, Diels-Alder-Reaktion, G. Thieme-Verlag 1972) of cyclopentadiene or furan with suitable dienophiles, such as maleic acids acetylene dicarboxylic acid or acrylic acids or derivatives thereof, and optionally subsequent modification of the obtained bicyclic compounds, e.g. by reduction, hydrolysis, etherification or esterification. Thus, e.g. the compound (VII) can be synthesized by way of a Diels-Alder reaction of cyclopentadiene with acrylic acid methyl ester, subsequent reduction of the bicyclic adduct to 5-norbornene-2-methanol (XXVI) and etherification thereof with allyl bromide.
Special polymers according to the invention can be prepared in particular by ring-opening metathesis copolymerization of the known bicyclo[2.2.1]hept-5-en-2-ylmethyl methacrylate (XI) with a trimethylsilyl- or tetrahydropyranyl-protected, commercial bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid in the presence of a suitable molybdenum-carbene catalyst and subsequent removal of protective groups by acid hydrolysis. In an analogous manner, polymers according to the invention can also be obtained by copolymerization of 7-oxabicyclo[2.2.1]hept-5-en-2-ylmethyl methacrylate (X) with the known 7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid anhydride (XXII) in the presence of ruthenium(III) chloride in aqueous-alcoholic medium.
The polymer according to the invention is suitable in particular as constituent of cements, coating materials and composites, and in particular of adhesives. The polymer according to the invention is particularly preferably used as a dental material or a constituent of dental material, in particular as a constituent of dental adhesives. Its ability on the one hand to form a bond with the material to be fixed e.g. a composite material via existing polymerizable groups such as (meth)acrylate groups, and on the other hand to develop an adhesion-promoting interaction with the substrate such as in particular the dentine via carboxyl groups, proves to be advantageous.
When the polymer according to the invention is used as a constituent of dental materials, it is normally used in a quantity of 0.1 to 60, in particular 1.0 to 40, wt. %, relative to the dental material. In order to prepare the dental materials, the polymer according to the invention is in particular combined with polymerizable organic binders, cross-linking monomers, fillers, reactive fillers, polymerization initiators and/or further additives, such as customary stabilizers, e.g. hydroquinone monomethyl ether (MEHQ) or 2,6-di-tert.-butyl-4-methylphenol (BHT), UV absorbers, pigments, dyes or solvents.
Suitable as polymerizable organic binders are all binders which can be used for a dental material, in particular monofunctional or polyfunctional (meth)acrylates which can be used singly or as mixtures. Preferred examples of these compounds are methyl (meth)acrylate, isobutyl (meth)acrylate, cyclohexyl (meth)acrylate, tetraethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, hexanediol di(meth)acrylate, decanediol di(meth)acrylate, dodecanediol di(meth)acrylate, bisphenol-A-di(meth)acrylate, trimethylolpropane tri(meth)acrylate, 2,2-bis-4-(3-methacryloxy-2-hydroxypropoxy)-phenylpropane (bis-GMA) and the products of the reaction of isocyanates, in particular di- and/or triisocyanates, with OH group-containing (meth)acrylates. Particularly preferred examples of the last-mentioned products are obtainable by reaction of 1 mol of hexamethylene diisocyanate with 2 mol of 2-hydroxyethylene methacrylate, of 1 mol of tri-(6-isocyanatohexyl)biuret with 3 mol of 2-hydroxyethyl methacrylate and of 1 mol of 2,2,4-trimethylhexamethylene diisocyanate with 2 mol of 2-hydroxyethyl methacrylate.
The organic binders are normally used in the dental material according to the invention in a quantity of 0 to 90 wt. %.
Suitable as cross-linking monomers are in particular the above-named polyfunctional (meth)acrylates, in particular triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, bis-GMA or urethane di(meth)acrylates.
The cross-linking monomers are normally used in the dental material according to the invention in a quantity of 0 to 80 wt. %.
Examples of preferred fillers are quartz powder, glass ceramic powder and glass powder, in particular of barium silicate glasses, Li/Al silicate glasses and barium glasses, aluminas or silicas, very finely divided silicas, in particular pyrogenic or precipitated silicas, X-ray-opaque fillers such as ytterbium trifluoride.
The fillers are typically used in a quantity of 0 to 85 wt. %, relative to the dental material.
Above all, fluoroaluminosilicate glasses and other glasses used in glass ionomer cements come into consideration as reactive fillers. The reactive fillers are normally used in the dental material according to the invention in a quantity of 0 to 80 wt. %.
Particularly preferred dental materials according to the invention are light-curing glass ionomer cements, dentine adhesives and compomers.
Quite particularly advantageous glass ionomer cements, dentine adhesives and compomers and the respective components thereof are given below:
Light-curing Glass Ionomer Cements:
polymer according to the invention,
reactive glass powder, in particular customary fluoroaluminosilicate glasses with an average particle size of about 0.05 to 15 xcexcm (cf A. D. Wilson, J. W. McLean, Glasionomerzement, Quintessenz Verlags-GmbH, Berlin 1988, page 21 et seq.),
polymers with carboxyl groups, e.g. acrylic acid or maleic acid polymers, which optionally bear laterally bound groups capable of polymerization, e.g. (meth)acrylate groups,
photoinitiators and stabilizers,
H2O, and
cross-linking monomers.
Dentine Adhesives:
polymer according to the invention,
hydrophilic monomers, such as 2-hydroxyethyl (meth)acrylate or 2-hydroxypropyl (meth)acrylate or polyethylene glycol mono- or dimethacrylates or n-vinyl pyrrolidone,
carboxylic or phosphoric acids capable of polymerization, such as e.g. maleic acid or 2-(meth)acryloyloxyethyl dihydrogenphosphate,
cross-linking monomers,
water, alcohol or acetone and
photoinitiators and stabilizers.
Compomers:
polymer according to the invention,
glass powder, in particular fluoroaluminosilicate glasses customary for glass ionomer cements, with an average particle size of about 0.05 to 5 xcexcm (cf A. D. Wilson, J. W. McLean, Glasionomerzement, Quintessenz Verlags-GmbH, Berlin 1988, page 21 et seq.),
photoinitiators and stabilizers,
customary cross-linking monomers,
cross-linking monomers containing carboxyl groups, such as the reaction products of 2 mol of 2-hydroxyethyl (meth)acrylate or 2-hydroxypropyl (meth)acrylate with 1 mol of 5-(2,5-dioxotetrahydrofuryl)-3-methylcyclohex-3-ene-1,2-dicarboxylic acid anhydride or the dianhydrides of e.g. commercial tetrahydrofuran-2,3,4,5-tetracarboxylic acid, of cyclohexane-1,2,3,4,5,6-hexacarboxylic acid or of butane-1,2,3,4-tetracarboxylic acid, and corresponding reaction products of these multifunctional carboxylic acids with more than 1 mol of glycidyl methacrylate.
The dental materials according to the invention and the polymers according to the invention can be polymerized by heat, in the cold or by light. The known peroxides such as dibenzoyl peroxide, dilauroyl peroxide, tert.-butylperoctoate or tert.-butylperbenzoate can be used as initiators for hot polymerization. Moreover, 2,2xe2x80x2-azoisobutyric acid nitrile (AIBN), benzpinacol and 2,2xe2x80x2-dialkylbenzpinacols are also suitable.
For example, benzophenone and derivatives thereof as well as benzoin and derivatives thereof can be used as initiators for photopolymerization. Further preferred photoinitiators are the xcex1-diketones, such as 9,10-phenanthrenequinone, diacetyl, furil, anisil, 4,4xe2x80x2-dichlorobenzil and 4,4xe2x80x2-dialkoxybenzil. Camphor quinone is particularly preferably used. Moreover, the group of acyl phosphine oxides is also highly suitable for the initiation of photopolymerization. In order to accelerate the initiation, the photoinitiators are used preferably together with a reducing agent, particularly preferably with an amine, in particular an aromatic amine.
Radical-supplying redox systems, for example benzoyl or lauroyl peroxide together with amines such as N,N-dimethyl-p-toluidine, N,N-dihydroxyethyl-p-toluidine or other structurally related amines are used as initiators for cold polymerization.
The combination of photoinitiators with different redox systems has proved effective especially in the case of dental materials for the cementing of dental restorations, such as glass ceramic inlays, onlays, part-crowns and crowns. Combinations of camphor quinone, benzoyl peroxide and amines such as N,N-dimethyl-p-toluidine and/or N,N-cyanoethylmethylaniline are preferred.
The concentration of the initiators preferably lies in the range from 0.05 to 2.0 wt. %, particularly preferably in the range from 0.1 to 0.8 wt. %, relative to the dental material.